Importance of Acidic Components in Compounding Ammonia-Preserved Latex with Zinc Oxide

W. G. Wren

doi:10.5254/1.3540120

Importance of Acidic Components in Compounding Ammonia-Preserved Latex with Zinc Oxide

Rubber Chemistry and Technology ◽

10.5254/1.3540120 ◽

1943 ◽

Vol 16 (2) ◽

pp. 342-364

Author(s):

W. G. Wren

Keyword(s):

Zinc Oxide ◽

Hydrochloric Acid ◽

Experimental Work ◽

Controlling Factor ◽

Ammonium Salts ◽

Caustic Alkali ◽

Naturally Occurring ◽

Acidic Components

Abstract In view of the experimental work described above, it appears that changes in viscosity of zinc oxide-compounded latex are due largely to the presence of ammonium salts of naturally occurring acids. These salts enable zinc to pass into solution, and to be absorbed by the latex globules, thus giving rise to the thickening commonly experienced. The amount of zinc passing into solution is directly proportional to the amount of acid present, and it is therefore suggested that determination of the acids by either of the methods described (viz., titration to pH 11 with caustic alkali, or from pH 7 to the end-point with hydrochloric acid), would form a sound basis for the classification of latices in regard to their behavior on compounding with zinc oxide. The investigations thus indicate that the variability of latex is due, in part at least, to the presence of acidic substances and may, therefore, be controlled by preventing the formation of the acids, or by their removal. Summary.—It is demonstrated that naturally occurring acidic substances control the solubility of zinc oxide in ammonia-preserved latex, and it is concluded that they are probably the controlling factor in determining the increase in viscosity which occurs in latex compounded with zinc oxide. In support of this view, it has been shown that the addition of various types of acid to ammonia-preserved latex markedly increases thickening after mixing with zinc oxide, and that the removal of naturally occurring acids reduces the thickening. It is suggested that titration of the acids in latex by the methods described forms a sound basis for the classification of latices in regard to their behavior on compounding with zinc oxide.

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The Zinc Oxide Stability of Latex

Rubber Chemistry and Technology ◽

10.5254/1.3543426 ◽

1952 ◽

Vol 25 (3) ◽

pp. 641-650 ◽

Cited By ~ 3

Author(s):

G. E. van Gils

Keyword(s):

Zinc Oxide ◽

Sulfonic Acid ◽

Ammonium Salts ◽

Rubber Content ◽

Intrinsic Factors ◽

The Stability ◽

Zinc Cations ◽

Sodium Phosphates ◽

Acidic Components ◽

Different Origin

Abstract A review of the factors which determine the zinc oxide stability of latex has been given. The work of Lepetit and our own experiments lead to the conclusion that the zinc oxide stability of latex is determined in the first place by substances which promote the solubilization of zinc oxide (minus factors); in the second place by substances which stabilize the colloid against the activity of the complex zinc cations or reduce the activity of these ions (plus factors). It has been generally accepted that the higher the KOH number of a latex, the lower is the zinc oxide stability. Since the KOH number is based primarily on neutralization of the acidic components of the serum only, a general correlation with zinc oxide stability could not be found when latexes of different origin were examined. Intrinsic factors or factors depending on the properties of the latex itself that influence zinc oxide stability are: (1) the dry rubber content of the latex, where high values are accompanied by low zinc oxide stability values and vice versa; (2) the yellow content fraction of latex, which in increasing amounts adds to the stability of the latex; (3) the protein content of the latex which, when degraded either artificially or naturally, reduces the zinc oxide stability. The effect of materials added to latex on zinc oxide stability includes: (1) fatty acid and sulfonic acid soaps, which have only slight influence; (2) Emulphor-O, sequestering agents, and sodium phosphates and silicates, which have a stabilizing effect; (3) ammonium salts and amines, which have a marked destabilizing effect, although triethanolamine hydrochloride is not active. Quebrachitol has a slight destabilizing effect.

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The Rapid Semimicrovolumetric Determination of Sulfur in Natural and Synthetic Rubber Vulcanizates

Rubber Chemistry and Technology ◽

10.5254/1.3542680 ◽

1957 ◽

Vol 30 (1) ◽

pp. 354-361 ◽

Cited By ~ 1

Author(s):

Bella B. Bauminger

Keyword(s):

Zinc Oxide ◽

Sulfuric Acid ◽

Hydrochloric Acid ◽

Schematic Diagram ◽

Total Sulfur ◽

Synthetic Rubber ◽

Combustion Apparatus ◽

Mineral Fillers ◽

A Current

Abstract In the first part, a modified form of combustion apparatus for sulfur analyses is described, and the principle of the method and the apparatus itself are illustrated by a schematic diagram. In the determination of sulfur in natural-rubber, Butyl-rubber, and Krylene mixtures which contain no mineral fillers such as barytes and whiting, 50 mg. of finely divided vulcanizate is covered with aluminum oxide, decomposed in a current of oxygen at 1000° C, and the sulfuric acid formed is determined gravimetrically. An analysis requires about 30 minutes. Differences between the analytical values obtained and the calculated values never amount to more than ±1 per cent. In the second part of the work, a newly developed procedure for the determination of total sulfur in rubber mixtures which contain barytes, lithopone, whiting, etc., is described. The sample is covered with a mixture of vanadium pentoxide and zinc oxide and is then decomposed in a current of oxygen at 1000° C Here too the sulfuric acid which is formed is titrated acidimetrically. An analysis requires about one hour. The final part of the work deals with a new method for the determination of sulfur in synthetic-rubber vulcanizates, such as Neoprene, Perbunan, Hypalon, etc. The sulfuric acid formed by their combustion is precipitated by a hydrochloric acid solution of 4-amino-4′-chlorobiphenyl, and titrated with sodium hydroxide. Zinc, chlorides, and nitrates have no disturbing effects on the reaction. The method was tested with vulcanizates of known compositions and was found to give satisfactory results.

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THE ESSENCE, THE NEED FOR EVALUATION AND TYPES OF ECONOMIC POTENTIAL OF ENTERPRISES

International scientific journal Internauka Series Economical Sciences ◽

10.25313/2520-2294-2020-10-6405 ◽

2017 ◽

Author(s):

Olexandr Yemelyanov ◽

Keyword(s):

Economic Activity ◽

Business Strategies ◽

Enterprise Management ◽

Value Assessment ◽

Economic Potential ◽

Enterprise Value ◽

Development Assessment ◽

State Of The Environment

The formation of business strategies of enterprises should be based on a preliminary assessment of their current and future economic opportunities. Such an assessment is to establish the value of the total economic potential of enterprises and its individual varieties. The purpose of this study was to clarify the essence of the economic potential of enterprises, justify the need for its evaluation and selection of its types. The main approaches to interpreting the terms "potential" and "enterprise potential" are identified. These include resource, result, resource-result, resource-target, and result-target concepts. It is established that the potential of any object, including the enterprise, can be interpreted as a set of its external functional properties, which this object shows or can show in a certain state of the environment in which it is located. Accordingly, the assessment of the potential of an object should be based on the identification and determination of its external properties, taking into account the environment in which the object is located. The main situations in which there is a need for information about certain components of the economic potential of the enterprise are identified, and the types of this potential and the consumers of the information about their level, corresponding to these situations, are determined. In particular, such situations include management of production and sales, management of financial and economic results of the enterprise, management of enterprise development, assessment of the company's need for various types of resources, assessment of enterprise value, assessment of current and future impact of the enterprise on the economy of the country (region), etc. The features of classification of types of enterprise potential existing in the scientific literature are supplemented by the following ones: by the main types of economic activity, by the dynamics of changes in the economic and production system of the enterprise, by consequences for the subject of enterprise potential assessment, by the stages of economic activity, enterprise potential, etc. The obtained results make it possible to improve the understanding of the complex patterns that underlie the formation of the economic potential of enterprises.

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State Failure and the Political Violence Phenomenon: A Comparative Analysis of Iraq and Syria Cases

European Journal of Interdisciplinary Studies ◽

10.26417/ejis.v4i2.p170-177 ◽

2016 ◽

Vol 4 (2) ◽

pp. 170 ◽

Cited By ~ 1

Author(s):

K. Eylem Özkaya Lassalle

Keyword(s):

Cold War ◽

Political Violence ◽

State Failure ◽

The Political ◽

Collective Violence ◽

Short Run ◽

Definition Of ◽

The Cold War

The concept of failed state came to the fore with the end of the Cold War, the collapse of the USSR and the disintegration of Yugoslavia. Political violence is central in these discussions on the definition of the concept or the determination of its dimensions (indicators). Specifically, the level of political violence, the type of political violence and intensity of political violence has been broached in the literature. An effective classification of political violence can lead us to a better understanding of state failure phenomenon. By using Tilly’s classification of collective violence which is based on extent of coordination among violent actors and salience of short-run damage, the role played by political violence in state failure can be understood clearly. In order to do this, two recent cases, Iraq and Syria will be examined.

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